Biological and synthetic fibers may be exposed to chlorinating and/or brominating agents in a variety of ways.
For example, swimming is a popular form of exercise and pastime. By its nature, swimming requires immersing oneself in a body of water. People may swim in either natural bodies of water (such as lakes, oceans, rivers, etc.), or man-made swimming pools.
Man-made swimming pools (including traditional swimming pools, hot tubs, etc., collectively referred to generally herein as “pools”) are usually smaller than naturally occurring bodies of water. They are also usually self-contained structures, consisting of a finite body of water separated from the surrounding environment, for example by walls. Pools provide an aqueous environment that is kept within a biologically habitable temperature range, such as about 65-90° F. Some pools may be kept cooler or warmer. For example, a hot tub may be maintained at more than 90° F.
A swimmer brings a variety of living and non-living substances into the pool. For example, the swimmer's skin, hair, saliva, urine, sweat, and other secretions may come into contact with the pool water. Owing to the aqueous medium and adequate temperature, pools provide a suitable environment for living organisms, such as bacteria, to thrive.
Pools are usually treated with chemicals chosen to prevent the growth of harmful organisms, such as bacteria. Properly used, these chemicals keep the pool water substantially free from harmful contaminants. For example, many pools are treated with chlorinating agents (e.g., chlorine, hypochlorite salts such as calcium hypochlorite or sodium hypochlorite, hypochlorous acid) or brominating agents (e.g., bromine, salts comprising bromine, etc).
The chemicals used to treat pool water work by reacting with certain molecules that come into contact with the pool water. For example, these chemicals may react with bacteria's biologically important molecules, thereby killing the bacteria.
In addition to reacting with bacteria and other contaminants, however, some pool chemicals react with elements of the swimmer, such as the swimmer's body and/or the swimmer's attire. For example, the fibers that make up the exterior of the body, such as skin, hair, eyes, and nails (collectively referred to herein as “body fibers,” and intending to include keratinous fibers that make up the hair, skin, and nails, as well as mucous membranes), comprise proteins. By way of example, human hair is made largely from alpha keratin (α-keratin). Those proteins are made from amino acids. All amino acids, including those making up proteins, have one or more N—H bonds. In α-keratin, the most abundant amino acid is cystine, which accounts for about 15% of the protein. Monomeric L-cystine has two N—H bonds. The oxidized dimmer of cystine has four N—H bonds. When present within a protein, each cystine residue has one N—H bond.
The N—H bonds in the amino acids in body fibers can react with the chemicals found in pool water. For example, one or more N—H bonds in an amino acid in the protein of hair or skin can react with a chlorinating agent used in pool water to form N—Cl, an amino chloride. Notably, the reacted amino acid, now containing an N—Cl bond, is still part of the protein in the hair or skin.
Although a swimmer can rinse the residual pool water from his or her skin, hair, attire, etc., after swimming, such rinsing may not effectively eliminate all the adverse effects of exposure to the chemically-treated pool water. For example, where the body's proteins have chemically reacted with the pool chemicals, they are physically changed but, at least in part, remain part of the body, i.e. they are not all rinsed away such as during normal showering.
Those remaining pool chemicals can be released throughout the day, for example as a result of exposing the skin, hair, etc., to moisture, e.g. water. As discussed above, after swimming in a pool with a chlorinating and/or brominating agent, proteins of the human body may become chlorinated and/or brominated. Subsequent exposure of those chlorinated and/or brominated amino groups to water (e.g. rain or sweat) may release these volatile chemicals, which may be corrosive or irritating.
Some of these corrosive molecules may be harmful to body and/or textile fibers (e.g. clothing such as swimming attire), or may cause an unpleasant sensation upon contact with the body and/or clothing fibers. Additionally, some of the volatile molecules may be perceived by the nose when liberated from the body and/or clothing, giving rise to odors. These odors are commonly referred to as simply “chlorine” or “pool odor,” and are considered a more chemical odor, rather than the type of odor naturally produced by the body.
Also, when pool chemicals, such as chlorine or bromine, react with the biological molecules forming the skin and/or eyes, those reactions may cause irritation. For example, some swimmers report itchy or inflamed skin following swimming in pools. Some swimmers indicate that mucous membranes, such as the sensitive nasal skin, become itchy and irritated following swimming.
Although some people have reported liking “pool odor,” as reminiscent of the pleasures associated with swimming itself, others do not like pool odor or, if strong enough, find the odor irritating, such as to the eyes and lungs. Additionally, since the chemicals liberated may irritate the skin and/or damage the hair, many people wish to prevent “pool odor” and/or the symptoms associated with it.
As discussed above, rinsing or washing, e.g. body fibers, does not by itself completely eliminate pool odor and/or skin irritation. Mitigating (i.e. decreasing to some extent or eliminating entirely) the effects of exposure to chlorinating and/or brominating agents requires reversing the chemical reaction between those chemicals and the proteins making up the human body. This requires converting the amino-halide bonds, e.g., chloramine (N—Cl) and/or bromamine (N—Br) groups into amino (N—H) groups. However, the soaps, shampoos, and conditioners currently known do not effectively convert N—Cl and/or N—Br bonds on body fibers back into N—H bonds. Accordingly, N—Cl and/or N—Br remain bonded to the body fibers following rinsing, washing, shampooing, and/or conditioning the body fibers, such as the skin and/or hair.
Some known shampoo and soap formulations are directed to mitigating the effects of exposure to chlorinating and/or brominating agents. For example, U.S. Pat. No. 4,295,985 discloses “a method of removal of chlorine retained by human skin and hair after exposure to chlorinated water, and soap and shampoo compositions adapted to effect said removal.” That patent teaches applying urea and thiosulfate salts to the hair and/or body following exposure to chlorinating agents.
Other known formulations have sought to remove minerals from hair in an effort to prevent discoloration of the hair. For example, U.S. Pat. No. 5,804,172 discloses compositions aimed at removing mineral deposits from hair exposed to hard water, particularly the calcium, magnesium, iron, and copper present in some municipal water sources. That patent discloses compositions including four ingredients, which are said to remove minerals from the hair due to the “synergistic combination” of ingredients. Within those compositions, a reducing agent, such as ascorbic acid, is included in an amount chosen to reduce oxidized cysteine-iron bonds. The patent discloses four-component compositions comprising 2.1 percent w/w of ascorbic acid, which is said to be sufficient to reduce the oxidation state of iron ions bonded to hair.
Additional known formulations have sought to remove chlorine from hair by treating the hair with ammonium lauryl sulfate, cocamide diethanolamine, sodium bicarbonate, cocobetaine, and water. See U.S. Pat. No. 4,547,364.
Finally, a host of other formulations promise to treat damaged hair and/or skin following exposure to swimming pools by using various combinations of ingredients. For example, U.S. Pat. No. 4,690,818 discloses a combination of hair and skin conditioners and moisturizers, namely, “a combination of cocodimonium hydrolyzed keratin and a mixture of monosaccharides and disaccharides . . . . ”
Further, chlorine (including, for example, gaseous or solvated Cl2, chlorine-comprising oxidizing agents, and salts thereof) has a multitude of uses in both household and industrial applications. For example, it can be used for disinfecting, whitening, bleaching, and clarifying materials. Chlorine is often used as an antimicrobial agent. For example sodium hypochlorite (a chlorinating agent) is known to kill a broad array of microbes. Owing to the efficacy, cost, and versatility of chlorinating agents, they are amazingly attractive reagents for a variety of home and industrial applications.
A down side to using chlorinating agents in the home and industry is that they can react with many of the materials to which they are exposed—often materials that the user would like to keep free from chlorination. Because materials and surfaces that are exposed to chlorine and chlorinating agents undergo a chemical reaction with the chlorine, their chemical composition becomes altered. Part of the chlorine and/or chlorinating agent becomes bound to the material or surface. Accordingly, one cannot simply wash away the residual chlorine. The bound chlorine must first be liberated before it can be washed away.
By way of non-limiting example, one may desire to kill microbes present on a particular surface, without altering the makeup of the surface that is disinfected. A user may, for example, wish to sterilize biological materials, metal, glass, textiles, floors, etc. with a chlorinating agent, but not wish to chlorinate the surface. If the chlorine is not liberated, it can react with other molecules that later come into contact with the material or surface.
And yet further, in the food industry, it may be desired to chlorinate the water that is used to chill poultry carcasses, such as chicken, but chicken producers would like to avoid chlorinating the biological tissues making up the chicken. Poultry is an important part of the worldwide animal food market. The poultry industry raises chickens, kills them, and then processes them into a form that is both convenient and safe for the consumer to use in preparing meals. Converting live chickens into healthy food presents challenges to the chicken industry. In particular, poultry provides an excellent medium for the growth of microorganisms, such as Pseudomonas, Staphylococcus, Micrococcus, Acinetobacter, Moraxella, and Salmonella. 
Even a healthy chicken harbors a considerable amount and variety of microorganisms, such as bacteria. These bacteria can be present on the chicken's feathers, feet, skin, and/or innards. During the slaughtering and processing procedures, bacteria present on the chicken may be carried along to subsequent processing steps. Preventing microbial contamination is immensely important throughout each aspect of chicken processing.
When the birds have reached “harvest” time, they are deprived of food and water. This allows their digestive tracts to empty so that less feces and undigested food enter the later processing steps. Minimizing these products of the digestive system reduces the overall potential for contaminating the chicken during processing. The chickens are usually stunned before killing them. Stunning knocks the birds unconscious but it does not kill them. The birds are killed either by hand or by a mechanical rotary knife that cuts the jugular veins and the carotid arteries at the neck. The birds are permitted to bleed for a fixed amount of time, depending on size and species (e.g., bleeding times of about 1.5 minutes for broilers).
Following bleeding, the birds go through scalding tanks. These tanks contain hot water that softens the skin, making it easier to remove the feathers. During scalding, the temperature of the water is carefully controlled, at least in part to control the chickens' color. If retaining the yellow skin color is desired, a soft-scald is used (about 50° C. or 122° F.). If a white bird is desired, a higher scald temperature is used, resulting in the removal of the yellow pellicle. Turkeys and spent hens (egg-laying birds that have finished their laying cycles) are generally run at higher temperatures-59° to 60° C. (138° to 140° F.).
After bleeding and scalding, the carcasses go through the feather-picking machines, which beat off the feathers with rubber fingers. Throughout the feathering process, the carcasses are moved through a sequence of machines, each optimized for removing different sets of feathers. Then, the carcasses may be singed by passing through a flame that burns off any remaining feathers.
After feathering, the chickens' heads are pulled off mechanically; their legs are removed with a rotary knife (much like a meat slicer). Then, the preen, or oil, gland is removed from the tail; the vent is opened so that the internal organs can be removed (“evisceration”).
Evisceration can be performed either by hand or by using an automated mechanical device. Automated evisceration lines can operate at a rate of about 70 birds per minute. The evisceration equipment is cleaned (with relatively high levels of chlorine) after each bird.
After eviscerating the chicken, the remaining carcasses are further cleaned. The viscera are separated from the carcasses. The edible offal are removed from the inedible offal. (The heart, stomach, and liver are all considered edible offal and are independently processed). Stomachs are usually cut open and the inside yellow lining of the stomach along with the stomach contents are removed.
The lungs and kidneys are removed separately from the other visceral organs using a vacuum pipe. The carcasses are then washed thoroughly. After the carcasses have been washed, they are chilled to a temperature below 4° C. (40° F.). The two main methods for chilling poultry are water chilling and air chilling. Water chilling is performed in chlorinated water.
Water chilling is used throughout North America and involves a pre-chilling step in which a countercurrent flow of cold water is used to lower the temperature of the carcasses. The carcasses are then moved into a chiller—a large tank specifically designed to move the carcasses through in a specific amount of time. Multiple tanks are often used to minimize cross-contamination.
A specified overflow of water for each tank is required by law in the United States and Canada. Although this renders the chilling process very water-intensive, it helps to minimize bacterial cross-contamination by diluting the microorganisms washed off the carcasses, thereby preventing recontamination.
During chilling, raw carcasses—already de-feathered and eviscerated, as described above—are submerged in cold water. The bath chills the birds to 40° F. or lower, preserving its freshness and lengthening its shelf life. The carcasses entering this chilling bath may be warm because the bird's living temperature was warm and, after killing, hot water was used in scalding/defeathering. Owing to the warm temperature of these carcasses, they provide a suitable temperature for bacterial proliferation.
In poultry processing plants, thousands of poultry carcasses share communal chiller tubs. To prevent microorganisms carried by some chickens from contaminating the water and infecting other birds in the bath, many processors use chlorine to sanitize the water. This bath “is a critical point in the plant's control of cross-contamination by these microorganisms.” Wood, M., Agricultural Research, September, 1994. In some commercial plants, the tanks are about 4 ft.×10 ft.×40 ft. and contain approximately 100,000 gallons of chilled, chlorinated water at around 33° F. They can have as many as a few thousand chickens in them at one time, on a continuous basis, for three shifts a day, with one two-hour cleanup period every 24 hours. The U.S.D.A. requires the plant operators to maintain a 38 ppm total chlorine residual in these tanks to provide adequate sanitation. Accordingly, during the chilling phase, the chicken is soaked in chlorinated water.
Exposing the chicken carcass to chlorinated water can lead to undesirable effects on the chicken ultimately entering the marketplace. In addition to reacting with bacteria and other contaminants, as desired, any chlorine present in the chiller water reacts with the body fibers of the eviscerated chicken. The body fibers that make up the exterior of the chicken comprise proteins made from amino acids, which, as described above, have one or more N—H bonds.
Similarly to that described above with regard to swimming, the N—H bonds in the amino acids making up chicken protein can react with the chlorine in chlorinated water. For example, one or more N—H bonds in an amino acid in the protein of the chicken can react with a chlorinating agent to form N—Cl, an amino chloride. Notably, the reacted amino acid, now containing an N—Cl bond, is still part of the chicken protein.
As also described above, although the residual chlorinated water can be rinsed off after a chicken is removed from the chiller, that sort of rinsing may not effectively eliminate all the adverse effects of exposure of the chicken carcass to the chemically-treated water. For example, where the chicken's proteins have chemically reacted with one or more chlorinating agents, they are physically changed but, at least in part, remain part of the chicken, i.e. they are not all rinsed away by normal rinsing.
The remaining chicken-bound chemicals can be released after the chicken is packaged and sent to the marketplace. For example, chlorine-containing molecules may be released by exposing the chicken to additional water, pH changes, or merely allowing for the passage of time. As discussed above, after exposing chicken to chlorinated water, the chicken's protein may become chlorinated. Subsequent exposure of those chlorinated amino groups to air and water may release chlorine containing chemicals, which may cause packaged chicken to have undesirable properties. For example, the chicken may have an undesirable odor (e.g., of “chlorine” or “bleach”), the chicken may lose depth of color, and/or the chicken may include residual chloride and/or hypochlorite. Some of these released molecules may be harmful to the chicken meat.
Faced with the undesirable post-processing chlorine smell and taste, some members of the chicken industry have attempted to process chickens without using chlorinating agents. But, using chlorinated water during at least the chilling process has proven so effective as an antimicrobial, that for safety reasons it is desired to continue to use this process. Accordingly, there remains a need to eliminate the residual undesirable affects of chlorine on the chicken.
However, there still exists a need for a convenient and effective method for mitigating the effects of chlorinating and/or brominating agents and other adverse effects on biological fibers (e.g., skin and eye itching and irritation) and/or synthetic fibers, such as textiles exposed to chlorinating and/or brominating agents, or water having chlorinating and/or brominating agents in it.
There remains a need in various industries, therefore, to mitigate adverse effects of exposure to oxidizers, such as chlorinating and brominating agents.